Create the tag ref

ugit/base.py

@@ -96,6 +96,8 @@ def commit(message):
 
     return oid
 
+def create_tag(name, oid):
+    data.update_ref(f"refs/tags/{name}", oid)
 
 def checkout(oid):
     commit = get_commit(oid)

ugit/data.py

@@ -11,13 +11,16 @@ def init():
 
 
 def update_ref(ref, oid):
-    with open(f"{GIT_DIR}/{ref}", "w") as f:
+    ref_path = f"{GIT_DIR}/{ref}"
+    Path.mkdir(ref_path, exist_ok=True)
+    with open(ref_path, "w") as f:
         f.write(oid)
 
 
 def get_ref(ref):
-    if Path.is_file(f"{GIT_DIR}/{ref}"):
-        with open(f"{GIT_DIR}/HEAD") as f:
+    ref_path = f"{GIT_DIR}/{ref}"
+    if Path.is_file(ref_path):
+        with open(ref_path) as f:
             return f.read().strip()